A contractor just replaced some siding for me by my back steps. I'm about to paint the whole exterior of the house, including the new siding, but the new stuff wasn't even pre-primed before installation and is now between stairs and flashing, and completely inaccessible.

Besides getting them to rip it out, and then prime and paint before installation, any suggestions on what to do?

Should I caulk along the top side of the flashing? Will that unprimed siding below the flashing just rot out quickly? (I'm in a wet area, that's the north side of the house).

Not sure what he was trying to do with this flashing. The first board on the deck should have been removed and the flashing should be behind the house wrap and over the rim joist. Replace the deck board and the siding stops just above the deck. This pictureshows the siding behind the deck board but painting the siding becomes impossible.

Right, I think flashing was also installed behind the siding and wrap — over the rim joist — but then this extra piece on the outside too. The ledger for these stairs is away from the siding with spacers.

But, given this situation, is there any way that I can prime and paint this adequately, because there's always going to be bare siding behind that flashing.

I agree with Neal. It is flashed wrong as the nails/flashing top edge are visible on top the T1-11 siding instead of underneath it in the first pic. Water will run down the grooves in the siding and rot it very quickly as no air movement to dry and flashing at bottom of ledger will collect it there. Capillarity/gravity will keep the bottom of the structural sheathing wet/damp and rot for sure because of cover. Add more lag screws per Table in here; http://www.awc.org/Publications/DCA/DCA6/DCA6-09.pdf.

It appears they flashed the siding without removing/reinstalling the first two deck boards; lame- it is guaranteed to leak. Lack of paint is the least of your concerns.... also pull one of the diagonal nails in any hanger- they should be 3" long; minimum; 2x6- LUS- into joist; http://www.strongtie.com/products/co...ce_ss-df1.asp# If those are indeed labeled (LUS).